'rest' events have dur nil

[adcxyz]

when a wavesetsevent-generated event has type \rest, it has a duration of nil,
which can be surprising when you use event[\dur] to calculate other values -
It took me a long while to figure out where exactly a rare error in a wavesets patch happened.

Maybe WavesetsEvent should have an instance variable restDur with a safe default value,
e.g. 0.01 or so, so even if it goes into a no-wavesets=found loop, it does not lock up?

[telephon]

Hm, could we risk to make it zero?